Our broad goal is to understand the complex developmental relationships between language and affect, two expressive human systems for communication. This project will chart the neuro-developmental trajectories of the cognitive domains of language, affect and discourse in normal and experimental population: children with unilateral Focal Lesions, (FL) Language Impairment (LI), Autism (AUT) and two genetically based forms of mental retardation, Williams Syndrome (WMS) and Down Syndrome (DNS). This project provides a clearly-defined forum for the investigation of cross-population hypotheses with respect to the development and integration of these two communicative systems. This project will serve as a center for measures of language development in narrative discourse and experimental language tests this project will also will break new ground in characterizing affective development across childhood as an independent system, and in relation to linguistic communication in a discourse context. Our initial findings are intriguing, and raise fundamental issues about the neuroanatomical organization of language and affect of their interface in children. In adults, affect is predominantly a right hemisphere function whereas language is mediated by the left hemisphere. This raises the following fundamental issues: To what degree is there re-organization and compensation in children: What is the course of development in the face of differential language deficits? To what extent do the trajectories of our atypical populations map onto or dissociate from normal; To explore these issues, we propose a comprehensive and hypothesis driven battery of experimental tasks. Our overall goal is three=-pronged; To understand the functional relationships and underlying neural substrates of effect and discourse, To map our developmental changes within and between these two communicative domains across the period from 5 years to adolescence, and To characterize and contrast normal developmental profiles with those that are observed in our experimental populations (FL, LI, WMS, DNS, AUT). Finally, cross-population studies will enable us to identify those elements which are dissociable within and across domains as well as address issues of localization of function and brain plasticity. Thus, in addition to its service functions ina the measurement of language development this project will address basic questions about the co-development of language and affective communication and their neural substrates. These studies have implications for diagnoses and interventions for a broad range of children with disorders of language and communication.